The new synthetic menthol plant of Haarmann & Reimer

At an elaborate reception ceremony, Haarmann & Reimer GmhH dedicated its new menthol plant in Bushy Park, South Carolina. This new plant is in continuous production, producing only l-menthol. The total employment at this plant is 49, with 32 people in production. These 32 operate the plant 24 hours a day, seven days a week. The process is a very intricate and complicated series of completely continuous operations combined with automatic sequencing batch processes. An extensive series of recorders and controllers allow the complete plant to be monitored and operated from a fifty foot long indicating, recording and control panel. The plant at Bushy Park, South Carolina is on property adjacent to another Bayer subsidiary, Mobay Chemical Company. Steam and other process services are supplied to the menthol plant from the Mobay manufacturing complex.

In the H&R synthetic menthol process, thymol is prepared via the alkylation of metacresol. Its subsequent hydrogenation yields a mixture of four racemates of isomeric menthols. From this mixture pure d-, l-menthol is isolated and the remaining menthol isomers are recycled. The racemic menthol is separated into the pure l-menthol and pure d-menthol antipodes. The l-menthol is crystallized and compacted into pellets while the d-menthol is recycled.

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